CN1241418C - White balance regulator and method thereof - Google Patents

Abstract

Disclosed is a white balance adjustment device, comprising: a cut-off value adjusting part for adjusting and outputting a cut-off value of an analog image signal input as a first graphic; an A/D converter for converting the analog image signal whose cut-off value has been adjusted The image signal is converted into a digital image signal; the detection part is used to detect the least significant bit of each three-color excitation value of the digital image signal; the control part is used to change the level of the variable register of the cut-off value adjustment part from corresponding to the preset The first initial cutoff value of is adjusted upward until the least significant bit becomes different from the first initial cutoff value, and the level of the variable register is set to the first cutoff value just before the least significant bit becomes different from the first initial cutoff value value; and a storage portion for storing the first cutoff value.

Description

White balance adjusting device and method thereof

technical field

The present invention relates to a white balance adjustment device and method thereof, in particular to a white balance adjustment device and method for adjusting the cut-off point and saturation point of digital displays such as liquid crystal displays (LCDs) and plasma display screens (PDPs). This application is based on Korean Application No. 2002-27934, which is incorporated herein by reference.

Background technique

In order to display an analog image signal input from an external device on a digital display such as LCD and PDP, it is necessary to convert the analog image signal into a digital image signal. Therefore, it is very important to match the black level and white level of the analog image signal input from the external device with the digital value of the digital image signal.

Therefore, in order to completely reproduce the colors of images, digital displays used in TVs or monitors, etc., set cutoff points for adjusting the balance of red, green, and blue (RGB) colors in the black level that emits dark light, and adjust Saturation point for adjusting the balance of RGB colors in the white level of the light emission.

FIG. 1 is a block diagram showing a conventional white balance adjustment device.

Referring to FIG. 1 , the white balance adjustment device includes a level adjustment part 100 , an A/D converter 110 , a data detection part 120 , a control part 130 , and a display part 140 . The level adjusting part 100 variably adjusts the levels of the variable registers to set cutoff points and saturation points of RGB color signals input from an external device. The A/D converter 110 converts the analog RGB color signals output from the level adjustment part 100 into 8-bit digital signals.

The data detection section 120 detects all data of the 8-bit digital RGB color signal. The control part 130 compares all data of the 8-bit digital RGB color signal detected from the digital detection part 120 with a predetermined standard value, and then controls the level adjustment part 100 to adjust the variable register according to the comparison result. The display part 140 receives the signal output from the data detection part 120, and drives the liquid crystal to display on the screen.

For example, the control part 130 initializes the cutoff point to desired data 0x00 in order to adjust the cutoff point of the RGB color signal input from the external device. Further, after the cut-off point is initialized, the control part 130 sets the level of the level adjustment part 100 to a desired value to complete the adjustment of the cut-off point. The control section compares the 8-bit data of the RGB color signal detected by the data detection section 120 with desired data.

If the data detected by the data detection part 120 is equal to the desired data, the control part 130 controls the level adjustment part 100 to gradually increase the level of the variable register until an optimum cut-off point is obtained. The level adjustment part 100 adjusts the level of the variable register according to the control signal of the control part 130 . If the 8-bit data of the RGB color signal read from the adjusted variable register of the level adjustment part 100 is larger than expected data, the corresponding level of the variable register is set as a cutoff point.

To set the saturation point, initialize the saturation point to the desired data 0xFF. After setting the variable register to a desired value, the control part 130 compares the RGB signals read from the data detection part 120 with the original data.

If the data detected by the data detection part 120 is equal to the desired data, the control part 130 controls the level adjustment part 100 to gradually decrease the level of the variable register until an optimum saturation point is obtained. The level adjustment part 100 adjusts the level of the variable register according to the control signal of the control part 130 . If each data corresponding to the RGB color signal read from the adjusted variable register of the level adjusting part 100 is smaller than desired data, the corresponding level of the variable register is set as a saturation point.

However, in the conventional white balance adjustment device, since the data detection section 120 must read all 8-bit digital data corresponding to each digital RGB color signal output from the A/D converter 110, the problem is that the white balance adjustment device The circuit structure becomes complicated.

In addition, if the cutoff point and saturation are not optimized, when the input analog signal is converted into a digital image signal, signal distortion occurs, and the image signal corresponding to the dark part is cut off and thus not displayed, or the corresponding Image signals in bright parts are saturated and therefore not displayed.

Contents of the invention

The present invention was developed to solve the above-mentioned problems in the prior art. Therefore, an object of the present invention is to provide a white balance adjusting device and method thereof for optimally setting the cutoff point and saturation point of each RGB color signal for an image signal input to an LCD device or a PDP device, thereby minimizing the quantization loss during the conversion process of the signal to a digital image signal and improves color reproduction.

In order to solve the above-mentioned problems, the white balance adjustment device according to the present invention includes: a cut-off value adjustment part for adjusting and thereby outputting a cut-off value of an analog image signal input in the form of a first pattern or pattern; an A/D converter, It is used to convert the analog image signal whose cut-off value has been adjusted into a digital image signal; the detection part is used to detect the least significant bit of each three-color excitation value of the digital image signal; the control part is used to adjust the variable of the cut-off value The level of the register is adjusted upwards from the value corresponding to the preset first initial cutoff until the least significant bit becomes different from the first initial cutoff value, and will be variable just before the least significant bit becomes different from the first initial cutoff value The level of the register is set as the first cut-off value; and the storage part is used to store the first cut-off value.

When an analog image signal is input to the cutoff value adjusting part in the form of a second pattern, the control part adjusts the level of the variable register downward from a level corresponding to a preset second initial cutoff value until the least significant bit changes to is different from the second initial cutoff value, and the level of the variable register is set to the second cutoff value just before the least significant bit becomes different from the second initial cutoff value, and the second cutoff value is stored in the storage section.

Preferably, the white balance adjustment device further includes a pattern generating part for generating a first pattern and a second pattern of the analog image signal, wherein, when the first cut-off value is set, the control part controls the pattern generating part to generate the first pattern, And when the second cutoff value is set, a second graph is generated. Here, the first graphic is a black graphic, and the second graphic is a white graphic.

Also, the level of the variable register corresponding to the first initial cutoff value is 0x00, and the level of the variable register corresponding to the second initial cutoff value is 0xFF.

Preferably, the white balance adjustment device further includes a rectification filter for filtering noise components included in the digital image signal output from the A/D converter, wherein the detection section detects each of the digital image signals from which the noise components have been filtered. The least significant bit of a tristimulus value. In addition, the detection section may detect a higher bit one order higher than the least significant bit of each tristimulus value of the digital image signal.

In order to solve another problem, the method for adjusting white balance according to the present invention comprises the following steps: the level of the variable register is set to the level corresponding to the first initial cut-off value; Form the cut-off value of the analog image signal input; convert the cut-off value of the analog image signal output from the variable register into a digital image signal; compare the least significant bit of each tristimulus value corresponding to the digital image signal with the first initial cut-off value; and adjusting the level of the variable register upwards, wherein the transform step to the upward adjustment step are repeated until the least significant bit becomes different from the first initial cutoff value, and will be just at the time when the least significant bit becomes different from the first initial cutoff value The level of the variable register before the value is set to the first cutoff value.

Preferably, the method further includes the steps of: setting the level of the variable register to a level corresponding to the second initial cut-off value; adjusting and outputting the cut-off value of the analog image signal input in the form of the second graphic through the variable register ; converting the cutoff value of the analog image signal output from the variable register into a digital image signal; comparing the least significant bit and the second initial cutoff value corresponding to each three-color excitation value of the digital image signal; and adjusting the variable register downward level, wherein the steps of transforming through scaling down are repeated until the least significant bit becomes different from the second initial cutoff value, and will be the level of the variable register just before the least significant bit becomes different from the second initial cutoff value Set as the second cutoff value.

Here the first graphic is a black graphic, and the second graphic is a white graphic. In addition, the level of the variable register corresponding to the first initial cutoff value is 0x00, and the level of the variable register corresponding to the second initial cutoff value is 0xFF.

According to the present invention, since the first and second cutoff points are adjusted using only the least significant bits corresponding to each RGB color signal, its circuit structure is simple. In addition, since an analog image signal input from an external device is converted into a digital image signal within a range between the first cutoff point and the second cutoff point, signal distortion is minimized. Color reproduction is improved because the display area of the digital display is maximized.

Description of drawings

By describing preferred embodiments of the present invention in detail in conjunction with the accompanying drawings, the above-mentioned purpose and other advantages of the present invention will become clearer, wherein:

FIG. 1 is a block diagram showing a conventional white balance adjustment device.

Fig. 2 is a block diagram showing a white balance adjusting device of one embodiment of the present invention.

FIG. 3 is a flow chart showing the method for adjusting white balance of the present invention.

Detailed ways

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

Fig. 2 is a block diagram showing a white balance adjusting device of one embodiment of the present invention.

With reference to Fig. 2, white balance adjustment device comprises figure generation part 200, cut-off value adjustment part 210, A/D converter 220, scaler 230, rectification filter 240, detection part 250, control part 260, storage part 270, and Display portion 280 .

The pattern generation part 200 generates an analog image signal in the form of first and second patterns or patterns according to a control signal of the control part 260 .

The cutoff value adjusting part 210 adjusts and outputs the cutoff value of the analog image signal input in the form of a first graph. Here, the first graphic is a black graphic, and the second graphic is a white graphic.

The A/D converter 220 converts the analog image signal output from the cutoff adjustment part 210 into a digital image signal.

The scaler 230 converts the digital image signal in units of frames to be displayed on the display of the display part 240 .

The rectification filter 240 filters out noise components included in the digital image signal output from the scaler 240 .

The detection section 250 detects the least significant bit of each three primary color excitation values (for example, RGB color signals) of the digital signal from which the noise component has been filtered out by the rectification filter 240 .

The control section 260 adjusts the level of the variable register of the cutoff value adjustment section 210 upward from a level corresponding to the preset first initial cutoff value until the least significant bit becomes different from the preset first initial cutoff value. The control section 260 sets the level of the variable register to the first cutoff value just before the least significant bit becomes different from the preset first initial cutoff value. Here, the level of the variable register corresponding to the first initial cutoff value is 0x00.

When an analog image signal in the form of a second pattern is input to the cut-off value adjustment section 210, the control section 260 adjusts the level of the variable register downward from a level corresponding to a preset second initial cut-off value until the least significant bit becomes different from the preset second initial cutoff value. The control section 260 sets the level of the variable register to the second cutoff value just before the least significant bit becomes different from the preset second initial cutoff value. Here, the level of the variable register corresponding to the second initial cutoff value is 0xFF. The first and second cutoff values are stored in the storage section 270 . The display part 280 receives the RGB color signals output from the scaler 230, and drives the liquid crystal to display on the screen. Here, the first cutoff value refers to a cutoff point which is a point at which light is about to be emitted, and the second cutoff value refers to a saturation point which is a point at which light becomes brightest.

In order to set the first cutoff value of the input analog image signal, the control part 260 controls the pattern generation part 200 to apply the analog image signal input from the external device in the form of a black pattern. Further, the control part 260 controls the cutoff value adjustment part 210 to set the variable register of the cutoff value adjustment part 210 to the first initial cutoff value. The pattern generation part 200 applies an analog image signal input from an external device in the form of a black pattern according to a control signal of the control part 260 . The cutoff value adjustment part 210 sets the level of the variable register to 0x00 according to the control signal of the control part 260 .

The A/D converter 220 converts the analog image signal output from the cutoff value adjustment section 210 into an 8-bit digital image signal. The RGB color signals of the digital image data output from the A/D converter 220 are 8 bits each, so a total of 24 bits. The scaler 230 converts the digital image signal output from the A/D converter 220 in units of frames to be displayed on the screen of the display part 280 . In general, since the resolution of a digital display such as an LCD or PDP is determined by a panel, it is necessary to transform an input image into a state that can be displayed on the digital display.

The rectification filter 240 filters out noise components included in the 8-bit digital image signal output from the scaler 230 . The detection part 250 detects the 8-bit digital image signal from which the noise component has been filtered, that is, the least significant bit corresponding to each RGB color signal. In addition, the detection part 250 can detect both the least significant bit corresponding to each 8-bit RGB color signal output from the rectification filter 240 and a higher bit one order higher than the least significant bit in consideration of an error. Also, regarding the 8-bit RGB color signal, the detection section 250 can detect at least one bit from four higher bits.

The control section 260 compares the least significant bit corresponding to each RGB color signal detected by the detection section 250 with the first initial cutoff value, and then changes the level of the variable register of the cutoff value adjustment section 210 from the level corresponding to the first initial cutoff value The level is adjusted upwards until the least significant bit becomes different from the preset first initial cutoff value. The control section 260 sets the level of the variable register to the first cutoff value just before the least significant bit becomes different from the preset first initial cutoff value.

For example, in the case where the least significant bit changes from 0 to 1 and the level of the variable register is set to each of 0x4F, 0x53, and 0x55, the level of the variable register will be set just before the least significant bit changes from 0 to 1 , that is, 0x4E, 0x52, and 0x54 are set as the first cutoff value. Cutoff points 0x4E, 0x52, and 0x54 with respect to each RGB color signal are stored in the storage section 270 . Therefore, after setting the first cutoff value, the variable register of the cutoff value adjustment part 210 is set to correspond to the first cutoff value of each RGB color signal stored in the storage part 270 .

If the setting of the first cutoff value is completed, the control part 260 controls the pattern generation part 200 to apply the analog image signal input from the external device in the form of a white pattern. Further, the control part 260 controls the cutoff value adjustment part 210 to set the level of the variable register of the cutoff value adjustment part 210 to the second initial cutoff value. The pattern generation part 200 applies an analog image signal input from an external device in the form of a white pattern according to a control signal of the control part 260 . The cutoff value adjustment part 210 sets the level of the variable register of the cutoff value adjustment part 210 to the second initial cutoff value according to the control signal of the control part 260 . Here, the level of the variable register corresponding to the second initial cutoff value is 0xFF.

The A/D converter 220 converts the analog image signal output from the variable register of the cutoff value adjustment part 210 into an 8-bit digital image signal. The scaler 230 converts the digital image signal output from the A/D converter 220 in units of frames to be displayed on a screen.

The rectification filter 240 filters out noise components included in the 8-bit digital image signal output from the scaler 230 . The detection part 250 detects the 8-bit digital image signal from which the noise component has been filtered out by the rectification filter 240, that is, the least significant bit corresponding to each RGB color signal.

The control part 260 compares the least significant bit and the second initial cutoff value corresponding to each RGB color signal detected by the detection part 250, and then adjusts the level of the variable register of the cutoff value adjustment part 210 downward from 0xFF until the lowest The valid bits become different from the preset second initial cutoff value. The control section 260 sets the level of the variable register to the second cutoff value just before the least significant bit becomes different from the preset second initial cutoff value.

For example, in the case where the least significant bit changes from 1 to 0 and the levels are 0x56, 0x61, and 0x74, the levels of the variable register just before the least significant bit changes from 1 to 0, that is, 0x55, 0x60, and 0x73 is set as the second cutoff value. Points 0x55, 0x60, and 0x73 with respect to each RGB color signal are stored in the storage section 270 as saturation points. Therefore, after setting the second cutoff value, the variable register of the cutoff value adjusting part 210 is set to the second cutoff value corresponding to each RGB color signal stored in the storage part 270 . The cutoff value adjustment section 210 is divided into variable registers for setting the first cutoff value and the second cutoff value, respectively.

FIG. 3 is a flow chart showing the method for adjusting white balance of the present invention.

Referring to FIG. 3, in order to set a cutoff point of an analog image signal input from an external device, the control part 260 initializes the level of the variable register of the cutoff value adjustment part 210 to 0x00 (S300). The control part 260 controls the pattern generating part 200 to input an analog image signal in the form of a black pattern. The pattern generation part 200 applies an analog image signal in the form of a black pattern according to a control signal of the control part 260 .

The cutoff value adjustment section 210 adjusts and outputs the cutoff value of the input analog image signal in the form of black graphics. The A/D converter 220 converts the analog image signal output from the cutoff adjustment part 210 into a digital image signal (S310).

The scaler 230 converts the digital image signal output from the A/D converter 220 to be displayed on the screen of the display part 280 . The rectification filter 240 filters out noise components included in the digital image signal output from the scaler 230 . The detection part 250 detects the least significant bit of each RGB color signal corresponding to the filtered noise component. The control part 260 compares the least significant bit corresponding to each RGB color signal detected by the detection part 250 with 0x00 (S320).

As a result of comparison in the process of S320, if the least significant bit corresponding to each RGB color signal has not changed, that is, the least significant bit is equal to the value 0x00, then the control section 260 adjusts the voltage of the variable register of the cutoff value adjustment section 210 upward. flat (S330). The control section 260 repeatedly executes the process of S330 until the least significant bit of each RGB color signal output from the process of S330 becomes different from the first initial cutoff value, that is, until each RGB color signal corresponding to the detection section 250 is detected. The least significant bit of the color signal changes from 0 to 1.

As a result of the processing at S320 or as a result of repeatedly executing the processing at S330, if the least significant bit of each RGB color signal is 1, the control section 260 sets the level of the variable register just before the least significant bit becomes 1 to the first A cutoff value (S340).

As described above, if the adjustment of the first cutoff value is completed, the control part 260 initializes the level of the variable register of the cutoff value adjustment part 210 to 0xFF in order to adjust the saturation point (S350). The control part 260 controls the graphic generation part 200 to input an analog image signal from an external device in the form of a white graphic. The pattern generation part 200 applies an analog image signal in the form of a white pattern according to a control signal of the control part 260 .

The cut-off adjustment section 210 adjusts and outputs an analog image signal input in the form of a white pattern. The A/D converter 220 converts the analog image signal output from the variable register into a digital image signal (S360). The scaler 230 converts the digital image signal output from the A/D converter 220 to be displayed on the screen of the display part 280 . The rectification filter 240 filters out noise components included in the digital image signal output from the scaler 230 .

The detection part 250 detects the least significant bit corresponding to each RGB color signal from which the noise component has been filtered out by the rectification filter 240 . The control part 260 compares the least significant bit corresponding to each RGB color signal detected by the detection part 250 with 0xFF (S370).

As a result of the comparison in the processing of S370, if the least significant bit corresponding to each RGB color signal detected by the detection section 250 has not changed, that is, the least significant bit is equal to the preset first initial cutoff value, then the control section 260 The level of the variable register of the cutoff value adjustment section 210 is adjusted downward. The control section 260 repeatedly executes the processing of S380 until the least significant bit of each RGB color signal output from the processing of S380 becomes different from the second initial cutoff value.

As a result of the processing at S370 or as a result of repeatedly executing the processing at S380, if the least significant bit of each RGB color signal detected from the detection section 250 is 0, the control section 260 will just when the least significant bit becomes different from the first The level of the variable register before the second initial cutoff value is set to a second cutoff value (S390). That is, the level of the variable register just before the least significant bit changes from 1 to 0 is set to the second cutoff value.

If the setting of the first and second cutoff values is completed, the variable registers of the cutoff value adjustment section 210 are set to the first and second section values. Then, the analog signal input from the external device is converted into a digital value within the range of the first cutoff value to the second cutoff value set by the cutoff value adjusting part 210 .

According to the white balance adjusting device and method thereof, when converting an analog image signal input from an external device into a digital image signal, the analog signal is converted into a digital value within a display range of a digital display. Therefore, a signal distortion phenomenon such that an image signal corresponding to a dark portion is cut off and thus not displayed, or an image signal corresponding to a bright portion is saturated and thus not displayed is avoided. Because the display range of the digital display is used to the maximum, quantization loss can be minimized, and color reproduction capability can be maximized.

Further, since the level of the variable register is adjusted after determining the least significant bit corresponding to each RGB color signal, the circuit structure of the white balance adjusting device is simple and can be easily applied. Furthermore, the present invention can be applied to various display models in the same adjustment method regardless of the signal processing device of the display such as a scaler.

Although the present invention has been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (11)

1. device is adjusted in a white balance, comprising:

Cutoff is regulated part, thereby is used to regulate and exports the cutoff of the analog picture signal of importing with the form of first figure;

A/D converter is used for the analog picture signal of adjusted cutoff is converted to data image signal;

The test section is used to detect the least significant bit of each tristimulus value(s) of data image signal;

Control section, be used for cutoff is regulated the level of variable register partly from adjusting upward corresponding to the first default initial cutoff, become different in the first initial cutoff up to least significant bit, and just in time before least significant bit becomes different in the first initial cutoff level of variable register be set to first cutoff; And

Storage area is used to store first cutoff.

2. device as claimed in claim 1, wherein when analog picture signal is input to the timesharing of cutoff adjusting portion with the form of second graph, control section with the level of variable register from adjusting downwards corresponding to the level of the second default initial cutoff, become different in the second initial cutoff up to least significant bit, and just in time before least significant bit becomes different in the second initial cutoff level of variable register be set to second cutoff, and in storage area the storage second cutoff.

3. device as claimed in claim 2, comprise that also figure produces part, be used to produce first figure and second graph about analog picture signal, wherein, when first cutoff is set, control section control figure generating unit divides generation first figure, and when second cutoff is set, produces second graph.

4. device as claimed in claim 2, wherein first figure is a black graphics, and second graph is white figure.

5. device as claimed in claim 2, wherein the level corresponding to the variable register of the first initial cutoff is 0 * 00, and is 0 * FF corresponding to the level of the variable register of the second initial cutoff.

6. device as claimed in claim 1, also comprise rectifier filter, be used for the noise component that filtering comprises from the data image signal of A/D converter output, wherein the least significant bit of each tristimulus value(s) of the data image signal of filter out noise component is detected in the test section.

7. device as claimed in claim 6, wherein more high-order than the least significant bit higher order of each tristimulus value(s) of data image signal detected in the test section.

8. method of adjusting white balance comprises:

The level of variable register is set to level corresponding to the first initial cutoff;

Regulate and export the cutoff of the analog picture signal of importing with the form of first figure through variable register;

To be transformed to data image signal from the cutoff of the analog picture signal of variable register output;

Compare the least significant bit and the first initial cutoff corresponding to each tristimulus value of data image signal; And

Adjust upward the level of variable register,

Wherein repeat shift step to adjusting upward step, become different in the first initial cutoff up to least significant bit, and just in time before least significant bit becomes different in the first initial cutoff level of variable register be set to first cutoff.

9. method as claimed in claim 8 also comprises:

The level of variable register is set to level corresponding to the second initial cutoff;

Regulate and export the cutoff of the analog picture signal of importing with the form of second graph through variable register;

To be transformed to data image signal from the cutoff of the analog picture signal of variable register output;

Compare the least significant bit and the second initial cutoff corresponding to each tristimulus value(s) of data image signal; And

Adjust the level of variable register downwards,

Wherein repeat shift step to downward set-up procedure, become different in the second initial cutoff up to least significant bit, and just in time before least significant bit becomes different in the second initial cutoff level of variable register be set to second cutoff.

10. method as claimed in claim 9, wherein first figure is a black graphics, and second graph is white figure.

11. method as claimed in claim 9, wherein the level corresponding to the variable register of the first initial cutoff is 0 * 00, and is 0 * FF corresponding to the level of the variable register of the second initial cutoff.

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